Network System

ABSTRACT

Power consumption on GMPLS controlled networks can be reduced by cutting power consumption on spare paths that are not normally used. To achieve power consumption reduction, in the path setting process, a path is calculated while taking the power saving capability of each interface into account, and the applicable interface is set to the power-saving state when setting the spare path. When the spare path was set to the operating state, then the power-saving state on the applicable interface was canceled so that interface could operate normally.

CLAIM OF PRIORITY

The present application claims priority from Japanese patent applicationJP 2007-250367 filed on Sep. 27, 2007, and JP 2008-176452 filed on Jul.7, 2008, the contents of which are hereby incorporated by reference intothis application.

FIELD OF THE INVENTION

This invention relates to power control of a spare path for acommunication equipment.

BACKGROUND OF THE INVENTION

A communication equipment with a spare path as shown in JP-A No.Hei-7(1995)-95132 can reduce overall power consumption in the equipmentby lowering power consumption of the interface board for the spare path.

A method disclosed in RFC3473 describes a method for notifyingequipments on whether a current path is in a main path or a spare pathby utilizing a GMPLS (generalized multiprotocol label switching)signaling protocol.

SUMMARY OF THE INVENTION

The method disclosed in JP-A No. Hei-7(1995)-95132 describes notechnique for deciding to switch from the main path to the spare pathand cannot inform other equipments occurrence of a fault in theinterface board of one equipment. Therefore, in that method, interfaceboards which are not directly connected to the fault-occurring equipmentcould not become lower power consumption status.

The technology disclosed in RFC3473 is capable of giving notificationthat a current path is in the spare path but contains no informationregarding power control of the interface board. Moreover this technologywas not able to decide whether to set the interface board for the sparepath to the power-saving state.

This invention is capable of lowering power consumption during thestandby state by installing power supply controlling unit to turn thepower to each component in the optical interface on and off, and byturning the power off to all or a portion of the interfaces that are ina non-operational state.

The GMPLS control unit contains a power control capability table showingthe power regulation performance in each interface unit of each opticalswitch, as well as a network topology table showing the connectionstatus between optical switches. While setting paths for the spare LSP(label switched path), the GMPLS control unit also adds restrictions tothe topology so that the path does not use the same nodes as the mainLSP, and sets an allowable recovery time as a limiting condition for theservice utilizing the LSP, and employs a path with a large power savingeffect as the spare path.

When switching to the spare path after a fault occurs on the main path,the GMPLS control unit instructs each GMPLS control unit on the sparepath to set the spare path to operating status. Each of these GMPLScontrol units sets the power supply controlling units for each interfacealong the spare LSP to normal operating status, and also cuts off alarmsissued from the interface units while within the allowable recoverytime.

This invention is capable of achieving power saving on the entirenetwork system which sets redundant (main and spare) LSP along multipleequipments LSP, by setting all interface units on the spare LSP to thepower-saving state, and, when a fault occurs on the main LSP, settingspare LSP to the normal state by cancelling the power-saving state inall interface units along the spare LSP.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing the network system of the first embodiment;

FIG. 2 is a structural drawing of the optical switching unit 20;

FIG. 3 is a structural drawing of the optical interface unit 206;

FIG. 4 is a drawing showing the structure of the GMPLS control unit 30;

FIG. 5 is a diagram showing the path setting process sequence;

FIG. 6 is a diagram showing the state change processing sequence for thespare path;

FIG. 7 is a drawing showing the data structure of the path message;

FIG. 8 is a diagram of the data structure of the network topology table;

FIG. 9 is a drawing showing the data structure for the power controlcapability table;

FIG. 10 is a drawing showing a switching state control table;

FIG. 11 is a drawing showing the IF power state control table;

FIG. 12 is a drawing showing the data structure of the path statecontrol table 330;

FIG. 13 is a drawing showing the structure of the service type recoverytime control table;

FIG. 14 is a flow chart showing the path calculation process 3500;

FIG. 15 is a flow chart of the IF state setting process 3600 during thepath setting;

FIG. 16 is a flow chart of the IF state setting process 3700 duringchanging of the path state;

FIG. 17 is a drawing showing the IF power state control table for theGMPLS control unit 30 d in step 503;

FIG. 18 is a drawing showing the switching state control table for theGMPLS control unit 30 d in step 504;

FIG. 19 is a drawing showing the IF power state control table for theGMPLS control unit 30 a in step 506;

FIG. 20 is a drawing showing the switching state control table for theGMPLS control unit 30 a in step 507;

FIG. 21 is a drawing showing the IF power state control table for theGMPLS control unit 30 d in step 512;

FIG. 22 is a drawing showing the switching state control table for theGMPLS control unit 30 d in step 513;

FIG. 23 is a drawing showing the IF power state control table for theGMPLS control unit 30 c in step 515;

FIG. 24 is a drawing showing the switching state control table for theGMPLS control unit 30 c in step 516;

FIG. 25 is a drawing showing the IF power state control table for theGMPLS control unit 30 b in step 518;

FIG. 26 is a drawing showing the switching state control table for theGMPLS control unit 30 b in step 519;

FIG. 27 is a drawing showing the IF power state control table for theGMPLS control unit 30 a in step 521;

FIG. 28 is a drawing showing the switching state control table for theGMPLS control unit 30 a in step 522;

FIG. 29 is a drawing showing the IF power state control table for theGMPLS control unit 30 d in step 607;

FIG. 30 is a drawing showing the switching state control table for theGMPLS control unit 30 d in step 608;

FIG. 31 is a drawing showing the IF power state control table for theGMPLS control unit 30 c in step 609;

FIG. 32 is a drawing showing the switching state control table for theGMPLS control unit 30 c in step 610;

FIG. 33 is a drawing showing the IF power state control table for theGMPLS control unit 30 c in step 611;

FIG. 34 is a drawing showing the switching state control table for theGMPLS control unit 30 c in step 612;

FIG. 35 is a drawing showing the IF power state control table for theGMPLS control unit 30 a in step 613;

FIG. 36 is a drawing showing the switching state control table for theGMPLS control unit 30 a in step 614;

FIG. 37 is a drawing showing the IF power state control table for theGMPLS control unit 30 d in step 616;

FIG. 38 is a drawing showing the switching state control table for theGMPLS control unit 30 d in step 617;

FIG. 39 is a drawing showing the IF power state control table for theGMPLS control unit 30 a in step 619;

FIG. 40 is a drawing showing the switching state control table for theGMPLS control unit 30 a in step 620;

FIG. 41 is a drawing showing the structure of the PATH message of 502;

FIG. 42 is a drawing showing the structure of the PATH message of 509;

FIG. 43 is a drawing showing the structure of the PATH message of 601;

FIG. 44 is a drawing showing the structure of the PATH message of 615.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of this invention are described next.

First Embodiment

The network system of the first embodiment is shown in FIG. 1.

The network system of this invention includes a one or more opticalswitch units 20, one or more GMPLS control units 30, a C-Plane network40, a D-Plane network 50, and a network management equipment 80. One ormore LSP (Label Switched Paths) 60 are set on the D-Plane network 50. Inthe figure and the description, a single optical switch unit 20 ispaired with a single GMPLS unit 30 to form four sets; however, anoptional number of these equipments can be set as required by thenetwork. Moreover, the optical switch unit and the GMPLS control unitneed not always be paired one to one, and a structure where one GMPLScontrol unit 30 controls multiple optical switching units 20 is alsoapplicable to this invention. These optical switching units 20 and GMPLScontrol units 30 may be mounted in individual cases or may be mountedwithin the same case.

When all the optical switching units 20 are joined by data linesallowing direct communication on the D-Plane network 50, that state iscalled adjoining connections. Moreover, if the optical switching unitscontrolled by the GMPLS control unit 30 are adjacently connected, theneven if the GMPLS control unit itself is indirectly connected (by arouter, etc.) for communication along the C-Plane network 40 and is notjoined by a line allowing direct communication, a network structure madeup of logical adjacent relations can be structured by utilizing forexample tunneling technology.

The present embodiment describes an example utilizing the opticalwavelength switching capability as the switching performance. However,this invention can still be applied unchanged even in other switchingunits using other switching capabilities such as for packets or TDMdefined for GMPLS.

An optical switching unit 20 contains one or more optical interfaces206. The optical switching unit 20 switches data among these opticalinterfaces 206.

The GMPLS control unit 30 communicates via the C-Plane network 40 basedon GMPLS protocols, sets, cancels and changes the LSP60 status.Moreover, GMPLS control unit 30 conveys these settings to the opticalswitching unit 20 and commands changes in the actual switching state.

The C-Plane network 40 is a packet network using an IP protocol.

The D-Plane network 50 is a set of lines (data lines) joining interfacesfor the optical switching unit 20.

The LSP60 is a logical path joining one or more data lines on theD-Plane network 50 and defined as a path from an interface to anotherinterface. Two LSP are specified in FIG. 1. One LSP is the LSP60 a,which is an LSP via the IF-2 of optical switching unit 20 a and the IF-1of optical switching unit 20 d forming a path from the IF-1 of opticalswitching unit 20 a to IF-2 of optical switching unit 20 d. The otherLSP is the LSP60 b which is an LSP via the IF-1 and IF-2 of opticalswitching unit 20 b from IF-3 of optical switching unit 20 a, IF-1 andIF-2 of optical switching unit 20 c, and IF-4 of optical switching unit20 d.

The components of optical switching unit 20 are shown in FIG. 2.

The optical switching unit 20 includes a CPU201, a memory 202, asecondary storage device 203, a communication interface 204, a switch205, and an optical interface 206. The embodiment of this invention canbe implemented if the switching unit contains one communicationinterface 204 but utilizing one or more communication interfaces 204does not present a problem.

FIG. 3 shows sub-components of the optical interface unit 206.

An optical interface unit 206 includes an internal interface unit 2061,a signal processing unit 2062, an O/E converter unit 2063, and E/Oconverter unit 2064, and a power supply controlling unit 2065.

FIG. 4 shows components the GMPLS control unit 30. The GMPLS controlunit 30 is made up of the CPU301, a memory 302, a secondary storagedevice 203, and one or more communication interfaces 204.

The data structure required to implement this invention is describednext.

FIG. 7 is a drawing showing the data structure of the PATH message. ThePATH message 700 contains an RSVP message type 701, and one or more RSVPobjects that are parameters of PATH message 700. The RSVP objectincludes the required objects such as the session identifier 702, anRSVP hop 703, a refresh period 704, and optional objects. Optionalobjects include the protection object 705, the service type 706, and theallowable recovery time 707. Other objects are objects 708, 709.

The protection object 705 is specified by RFC3473 and thedraft-ietf-ccamp-gmpls-recovery-e2e-signaling-04.txt. The protectionobject 705 includes a flag showing where the path is the main path orthe spare path, and a flag showing whether the spare path is in theoperating state or non-operating state.

The service type 706 is an object showing the type of service used onthe main path. When a path setting is initiated by signaling fromoutside this network system, the service type 706 indicates that aservice is utilizing the main path.

The allowable recovery time 707 is a parameter showing the upper limitfor the time required to shift the spare path from a non-operating stateto an operating state.

A description of the RESV message is omitted since this invention doesnot introduce new parameters.

FIG. 8 is a diagram of the data structure of the network topology table;

The network topology table 800 is stored in the memory 302 of the GMPLScontrol unit 30, and holds the D-Plane network 50 topology information.

The network topology table 800 includes fields for the endpoint A nodeID8001, endpoint A IF_ID8002, endpoint B node ID8003, endpoint BIF_ID8004, switching capability 8005, and the link attribute 8006.

The endpoint A node ID8001, endpoint A IF_ID8002, endpoint B node ID8003and endpoint B IF_ID8004 are respectively identifiers showing bothendpoints of the respective lines. The endpoint A and endpoint B sidesdo not indicate a particular order or sequence. The endpoint A nodeID8001 and the endpoint B node ID8003 are ID for showing the GMPLScontrol unit 30 for regulating the respective applicable opticalswitching units 20. The endpoint A node ID8001 and the endpoint B nodeID8003 generally utilize an IP address of GMPLS control unit 30. Theendpoint A IF_ID8002 and endpoint B IF_ID8004 are each ID numbers foridentifying the corresponding optical interface unit 206.

The switching capability 8005 indicates the switching capability foreach line for the packet, TDM and optical wavelength.

The link attribute 8006 is a field showing one or more line attributessuch as the line speed and transmission delay time.

FIG. 9 is a data structure table for the power control capability table.

The power control capability table 900 is in the memory 302 of GMPLScontrol unit 30, and contains the fields for node ID9001, IF_ID9002,power control states 9003, power states 9004 a-9004 c.

The node ID9001 and IF_ID9002 are utilized for identifying the targetinterfaces. The contents of node ID9001 are identical to endpoint A nodeID8001. The contents of IF_ID9002 are identical to the endpoint AIF_ID8002.

The power control states 9003 value indicates the power control statesused for the applicable interface. If this value is zero it indicatesthat power is constantly applied and there is no power controlcapability for the applicable interface.

The power state 9004 is present as 9004 a, 9004 b . . . according to thevalue in the power control states 9003, and shows the power-saving ratein each power state and time for recovery to the normal state.

In this embodiment, the power state is ST0 if power is constantlysupplied without power control (or power regulation); the power state isST1 if the power is off just for the internal interface unit 2061 withinoptical interface unit 206; the power state is ST2 if the power for thesignal processing unit 2062 and the internal interface unit 2061 areoff; the power state is ST3 if the power to the 0/E converter unit 2063and the E/O converter unit 2064 is off in addition to the signalprocessing unit 2062 and the internal interface unit 2061.

The data making up the network topology table 800 and the power controlcapability table 900 might be changed autonomously within each of theGMPLS control units 30 by using a routing protocol, or might be set inthe GMPLS control unit 30 by a management equipment outside this system.The present invention can be implemented in either of these cases.

FIG. 13 is a drawing showing the structure of the service type recoverytime control table;

The service type recovery time control table 1300 is inside the memory302 of GMPLS control unit 30 and contains the respective fields for theservice type field 1301 and the allowable recovery time field 1302.

The service type field 1301 is stored as a value matching the servicetype 706 of PATH message 700. The allowable recovery time field 1302 isstored as a value for the recovery time allowed for the applicableservice type.

Typical service types include dedicated lines, VoIP, general Internet,high-quality Internet, etc. Examples of the allowable recovery time forthese services are shown in the figure. The figure is only an exampleand this invention is not limited to the values in the figure.

The service type recovery time control table 1300 value is set based onthe operating policy of the administrator of this network system. Howthis value is determined is beyond the applicable scope of thisinvention.

FIG. 10 is a drawing showing a switching state control table.

A switching state control table 220 is stored in the memory 202 of theoptical switching unit 20, and controls the state of the switching unit205.

The switching state control table 220 contains respective fields for aninput IF field 2201, an output IF field 2202, and an IF state field2203.

The input IF field 2201 contains IF number for the input side of switch205. The output IF field 2202 contains IF numbers for the output side ofthe switch 205. The IF state field 2203 contains the IF state specifiedby the input IF field 2201.

The IF states are respectively: Not used; In-use; Reserved; and Problem.Here, Not Used indicates that the IF is not being utilized; In-useindicates that the IF is connected to the output IF; Reserved indicatesa path has already been set via that IF to serve for example as anauxiliary path during fault recovery but actually is in a state wherenot connected by the switch 205 to the input IF and output IF. Also,Problem (or fault) indicates that a fault has occurred in the input IF,and data communications cannot be performed.

The output IF field 2202 value is not used and its value is ignored ifin a state where the IF state field 2203 value is not in use.

FIG. 11 is a drawing showing the IF power status control table.

The memory 202 of optical switching unit 20 contains the IF power statecontrol table 230. The IF power state control table 230 controls thepower state of the optical interface unit 206.

The IF power state control table 230 contains respective fields for anIF_ID field 2301 and an IF power state field 2302.

An ID for the optical interface 206 serving as the object is stored inIF_ID field 2301; and the power state for the applicable interface isstored in the IF power state field 2302. The value for the IF powerstate field 2302 is specified in the power state 9004 of power controlcapability table 900.

FIG. 12 is a drawing showing the data structure of the path statecontrol table 330.

The path state control table 330 is data stored in the memory 302 ofGMPLS control unit 30; and stores the path state, that was set using theGMPLS protocol.

The path state control table 330 contains respective fields for asession ID field 3301, an input IF_ID field 3302, and input label field3303, an output IF_ID filed 3304, an output label field 3305, a statefield 3306, an allowable recovery time field 3307, another attributevalue field 3308.

The session ID field 3301 stores session ID values utilized foridentifying the path on the RSVP-TE protocol.

The input IF_ID field 3302, and input label field 3303, an output IF_IDfiled 3304, an output label field 3305 respectively store the inputside, and output side IF_ID values, and the label values.

The IF_ID and labels are defined by the GMPLS protocol, and are forintended for abstract and unified handling of switches operated byvarious transmission methods. In this embodiment, the IF_ID is anumerical value for specifying the optical interface 206 of opticalswitch 20, and the label is a numerical value for specifying thewavelength of the optical data input and output from the opticalinterface 206 of optical switch 20. The IF_ID and the label values arenumerical values. Each GMPLS control unit 30 sets these independentlyand notifies the connecting GMPLS control units 30 of these values. TheIF_ID and the label values are not related to any physical values (forexample, figures expressing the optical wavelength in nanometers, etc.)and only for making decisions on whether values are a match (size of thevalue is not significant).

In the RSVP-TE, the GMPLS control unit decides the IF_ID value forcontrolling that interface, and the label value is determined by thedownstream side or in other words, the side accepting the data so thatthe input IF_ID field 3302, and input label field 3303, an output IF_IDfield 3304 determine and store their own values; and the value in theoutput label field 3305 was a value stored after notification fromanother adjacent connecting downstream GMPLS control unit.

The state field 3306 stores each path state. These path states includethe “Operating” and the “Reserved” states.

The path is set in each GMPLS control unit 30 per that operating state.Moreover, even in the optical switching unit 20 the switch 205 is set tothe state matching that path setting. During the reserved state on theother hand, that path is set in each GMPLS control unit 30 but theswitch 205 of optical switching unit 20 is not yet set to a state.

The allowable recovery time field 3307 stores the value notified by theallowable recovery time 707 of PATH message 700.

The other attribute value field 3308 stores the various types of pathinformation defined by the RSVP-TE. The handling of the other fieldvalues is the same as the handling specified in RSVP-TE. There is noneed to make a change in the embodiment of this invention so a detaileddescription is omitted.

A summary of the fault recovery procedure for a D-Plane line fault inthe network of FIG. 1 is described next. This embodiment assumes thatdata communication is implemented on data input from IF-1 of opticalswitching unit 20 a and output from IF-2 of optical switching unit 20 d.

The fault recovery methods include a method for searching for asubstitute path after a fault occurs and setting the path; and a methodfor reserving a substitute path in advance, and making a quick recoveryby switching the path state after a fault occurs from the reserved stateto the operating state. The example in this embodiment employs thelatter method that sets a substitute path in advance. Therefore in FIG.1 two paths are set. One path is LSP60 a, which is set as the main path,and the other is LSP60 b, which is the spare path. The data usuallyflows on the LSP60 a path, and when a fault occurs on the data line forLSP60 a, the switching is changed in each optical switching unit 20 toswitch the data communication to the LSP60 b, which is the spare path.

FIG. 5 is a sequence diagram showing the process for setting the sparepath and the main path in the first embodiment. The event assumed toinitiate the path setting process may be multiple causes such as pathsetting instructions from a network processor equipment and signalingfrom an outside network and this invention can be implemented by any ofthese causes. In the example of this embodiment, the path setting isinitiated by instructions from the network management equipment 80.

The GMPLS signaling protocols include multiple protocols such as RSVP-TEand CR-LDP. The present invention can be implemented no matter which ofthese protocols are employed. The RSVP-TE protocol is utilized as thesignaling protocol in the example of this embodiment.

When setting the main path which is LSP60 a, first of all, the networkmanagement equipment 80 commands the GMPLS control unit 30 a controllingthe optical switching path unit 20 a serving as the path start point, tocalculate the main path in 501, and select a path to the opticalswitching unit 20 d as the path endpoint by way of IF-1 of opticalswitching unit 20 d, and IF-2 of optical switching unit 20 a serving asthe directly connected link.

Next, the GMPLS control unit 30 a sends a path message 502 serving as anRSVP-TE message requesting establishment of a path, to the GMPLS controlunit 30 d controlling the optical switching unit 20 d serving as theconnecting node and also as the path endpoint node.

FIG. 41 is a drawing showing the structure of the PATH message of 502.

After accepting the path message 502, the GMPLS control unit 30 dconfirms that the requested path can be set, sets the path requested tooptical switching unit 20 d in 502, 503, and sends an RESV message 505which is an RSVP-TE message showing a response to the path set requestcheck to the GMPLS control unit 30 a.

FIG. 17 is a drawing showing the IF power state control table for theGMPLS control unit 30 d to be set in step 503. FIG. 18 is a drawingshowing the switching state control table for the GMPLS control unit 30d to be set in step 504.

When the RESV message 505 is received, the GMPLS control unit 30 a setsthe main path in the optical switching unit 20 a in 506, 507 to completethe setting of the LSP60 a.

FIG. 19 is a drawing showing the IF power state control table for theGMPLS control unit 30 a to be set in step 506. FIG. 20 is a drawingshowing the switching state control table for the GMPLS control unit 30a to be set in step 507.

The process sequence for setting the spare path LSP60 b is shown next.The redundant processing method used during path setting such as settingthe spare path is specified as a parameter when starting to set the mainpath and is therefore outside the scope of the present invention.

The GMPLS control unit 30 a calculates the spare path in 504. This sparepath is a path using nodes different from the main path. The GMPLScontrol unit 30 a selects a path to the optical switching unit 20 d viathe optical switching units 20 b, and optical switching units 20 c asthe spare path. The optical switching unit 20 a and the opticalswitching units 20 d here are the respective start point and endpointwhich is common to both the main path and the spare path but the mainpath and spare path respectively utilize different interfaces so thatredundancy is acquired on the interface level.

The spare path calculation is made based not merely on topologyinformation between the optical switches as described later on but alsoby taking the power saving capability of interfaces having opticalswitches into account.

FIG. 42 is a drawing showing the structure of the PATH message of 509.

After calculating the path, the GMPLS control unit 30 a sends a PATHmessage 509 to the GMPLS control unit 30 b controlling the opticalswitching unit 20 b serving as the next connecting node. At this time, aparameter (parameter already specified by RSVP-TE) showing that the pathis a spare path and currently in the non-operating state is added to thePATH message 509, and a PATH message containing an allowable recoverytime as a parameter showing the maximum value for recovery time requiredfor switching the spare path from a non-operating state to an operatingstate is sent. In the current example, the service type 706 value isHigh Quality Internet, and the allowable recovery time 707 is 5 seconds.

After confirming that the specified path can be set, the GMPLS controlunit 30 b sends a PATH message 510 to the GMPLS control unit 30 ccontrolling the optical switching unit 20 c serving as the nextconnecting node. This PATH message 510 also includes the allowablerecovery time as a parameter, the same as PATH message 509.

Similarly, after the GMPLS control unit 30 c confirms that the specifiedpath setting is possible, it sends a PATH message 511 to the GMPLScontrol unit 30 d controlling the optical switching unit 20 d service asthe next connecting mode and also as the endpoint node. This PATHmessage 511 also includes the allowable recovery time as a parameter,the same as PATH message 509.

When the GMPLS control unit 30 d that controls the optical switchingunit 20 d serving as the endpoint node confirms that setting therequested path is possible, it sets the interface power control stateused in the spare system in 512 to the state with the highestpower-saving rate within the allowable recovery period indicated in PATHmessage 511, by making switch settings in 513. The joint recovery timein the current example is 5 seconds so ST2 is set as the power state.

FIG. 21 is a drawing showing the IF power state control table for theGMPLS control unit 30 d to be set in step 512. FIG. 22 is a drawingshowing the switching state control table for the GMPLS control unit 30d to be set in step 513;

The RESV message 514 is in this way sent to the GMPLS control unit 30 cand notification sent that path setting is complete.

The GMPLS control unit 30 c sets the power state of the spare interfacein the same way in 515, sets the switch state in 516, and sends the RESVmessage 517 to the GMPLS control unit 30 b.

FIG. 23 is a drawing showing the IF power state control table for theGMPLS control unit 30 c to be set in step 515. FIG. 24 is a drawingshowing the switching state control table for the GMPLS control unit 30c to be set in step 516;

The GMPLS control unit 30 b next sets the power state of the spareinterface in 518, sets the switch state in 519, and sends the RESVmessage 520 to the GMPLS control unit 30 a.

FIG. 25 is a drawing showing the IF power state control table for theGMPLS control unit 30 b to be set in step 518. FIG. 26 is a drawingshowing the switching state control table for the GMPLS control unit 30b to be set in step 519.

The GMPLS control unit 30 a sets the power state of the spare interfacein 521, and sets the switch state in 522 to complete the setting of thespare LSP60 b.

FIG. 27 is a drawing showing the IF power state control table for theGMPLS control unit 30 a to be set in step 521. FIG. 28 is a drawingshowing the switching state control table for the GMPLS control unit 30a to be set in step 522.

FIG. 6 is a process sequence diagram showing the changing of spare LSP60b from a non-operating state to an operating state, and changing themain path LSP60 a to a non-operating state.

The process for switching a redundant system utilizing GMPLS is carriedout by switching to the spare system by the GMPLS control unit servingas the path start point, sending a PATH message containing the pathstate change. The method for reporting an abnormality on the main pathto the path start point GMPLS control unit is beyond the scope of theGMPLS method and is also outside the scope of this invention which isnot dependent on a specific method. The example of the embodiment, showsthe case where the process for switching over to the redundant systemstarts by the optical switching unit 20 a sending a switchover requestfor the spare system path to the GMPLS control unit 30 a.

The GMPLS control unit 30 a sends a PATH message 601 containing aparameter showing that the path state has been changed from (sparesystem, non-operating) state to a (spare system, operating) state to theGMPLS control unit 30 b. Hereafter, the GMPLS control unit 30 b sendsthe PATH message 602 to the GMPLS control unit 30 c, and the GMPLScontrol unit 30 c sends the PATH message 603 to the GMPLS control unit30 d in the same sequence as when setting the path; and completes thechanging of the LSP60 from a non-operating state to an operating stateby sending the RESV message 604, RESV message 605, RESV message 606 inthe reverse direction. In this case, the GMPLS control units 30 d-30 aset the respective IF power control states to SO0 in 607, 609, 611, and613, and sets the switching unit 205 state in 608, 610, 612, and 614,And sets the spare LSP60 b to the operating state to allow the flow ofdata.

FIG. 29 is a drawing showing the IF power state control table for theGMPLS control unit 30 d to be set in step 607. FIG. 30 is a drawingshowing the switching state control table for the GMPLS control unit 30d to be set in step 608. FIG. 31 is a drawing showing the IF power statecontrol table for the GMPLS control unit 30 c to be set in step 609.FIG. 32 is a drawing showing the switching state control table for theGMPLS control unit 30 c to be set in step 610. FIG. 33 is a drawingshowing the IF power state control table for the GMPLS control unit 30 cto be set in step 611. FIG. 34 is a drawing showing the switching statecontrol table for the GMPLS control unit 30 c to be set in step 612.FIG. 35 is a drawing showing the IF power state control table for theGMPLS control unit 30 a to be set in step 613. FIG. 36 is a drawingshowing the switching state control table for the GMPLS control unit 30a to be set in step 614. FIG. 43 is a drawing showing the structure ofthe PATH message of 601.

Next, the GMPLS control unit 30 a sends a PATH message 615 containing aparameter showing that the path state has been changed from (mainsystem, operating) state to a (main system, non-operating) state to theGMPLS control unit 30 d. The GMPLS control unit 30 d sets the powercontrol state of the IF in 616, sets the switching unit 205 state in617, and sends the RESV message 618 to the GMPLS control unit 30 a. TheGMPLS control unit 30 a changes the main path to the non-operating stateby setting the power control state of the IF in 619, sets the state ofthe switching unit 205 in 620.

FIG. 37 is a drawing showing the IF power state control table for theGMPLS control unit 30 d to be set in step 616. FIG. 38 is a drawingshowing the switching state control table for the GMPLS control unit 30d to be set in step 617. FIG. 39 is a drawing showing the IF power statecontrol table for the GMPLS control unit 30 a to be set in step 619.FIG. 40 is a drawing showing the switching state control table for theGMPLS control unit 30 a to be set in step 620. FIG. 44 is a drawingshowing the structure of the PATH message of 615.

When setting the IF state in 607, 609, 611, and 613, the alarm showing acommunication error from the applicable IF during the allowable recoveryperiod that is reported during path setting is masked, and the warning(alarm) information is temporarily suppressed. Suppressing the alarm inthis way separates the alarm that unavoidably occurs during thetransition period from a non-operating to an operating state, from anactual equipment alarm, and serves to reduce the load on theadministrator.

FIG. 14 is a flow chart showing path calculation process 3500.

The path calculation process 3500 is a program executed by the CPU301 ofthe GMPLS control unit 30.

The path calculation process 3500 is executed via 501 and 508 of FIG. 5.

In the path calculation process 3500 whether to make the spare pathcalculation is first of all decided in step 3501. Whether or not tocalculate the spare path is decided by the value in the protectionobject 705 in PATH message 700.

In the case of the main path, the process proceeds to step 3502, thenetwork topology table 800 values are checked, and an appropriate pathis selected.

If the path is the spare path then the process proceeds to step 3503,the value of the service type 706 of PATH message 700, and the value ofthe service type recovery time control table 1300 are checked and thevalue of the allowable recovery time then found.

Next, in step 3504, path information for the main path (previouslydefined as the RSVP-TE object) and the allowable recovery time are setas limiting conditions, the network topology table 800 and power controlcapability table 900 are checked, and the path calculated with thecondition that the path is the maximum power saving path. The algorithmused for calculating the path under specified limiting conditions, is awell known as GMPLS protocol such as shown for example in RFC2702 andtherefore a detailed description is omitted here.

FIG. 15 is a flow chart of the IF state setting process 3600 during thepath setting.

The IF state setting process 3600 during path setting is a programexecuted by the CPU301 of the GMPLS control unit 30.

The IF state setting process 3600 during path setting is executed in512, 515, 518, and 521 in FIG. 5.

In the IF state setting process 3600 during the path setting a decisionis first made on whether the path set in step 3601 is the spare path ornot. The decision conditions are the same as in step 3501.

If the path that was set was not the spare path, then no particularpower control of the interface is being carried out so the processterminates.

If the spare path was set in step 3601 then the process proceeds to step3602, the path state control table 330 is checked, and a check made tofind whether the allowable recovery time was set for the path. If theallowable recovery time was not set then the process terminatesunchanged.

If the allowable recovery time was set, then the path state controltable 330 is checked in step 3603, and a check made on whether anotherspare path has already been set in the IF that must be set. If anotherpath has been set then a minimum value is found from among the allowablesetting times that were set in that IF, and that value is then newly setas the allowable setting time in step 3604.

Then in step 3605, the power control capability table 900 is checked,and the power state with the highest power-saving rate is found fromamong the power states satisfying the specified recovery time that wasset, and that value is rewritten into the IF power state control table230 by sending an instruction to the optical switching unit 20.

The communication protocol used here between the GMPLS control unit 30and the optical switching unit 20 is outside the applicable range ofGMPLS and is a vendor-specific protocol. In many cases, the TL/1protocol is utilized as this optical switching unit control protocol butother protocols are also applicable to the implementation of thisinvention.

FIG. 16 is a flow chart of the IF state setting process 3700 duringchanging of the path state.

The IF state setting process 3700 during path state changing is aprogram executed by the CPU301 of GMPLS control unit 30.

The IF state setting process 3700 during path state changing isimplemented by 607, 609, 611, 613, 616, and 619 of FIG. 6.

In step 3701 of IF state setting process 3700 during path statechanging, a decision is made whether to change the state to theoperating state, and if a change to the operating state, then theprocess proceeds to step 3702. If not a change to the operating state,then the process proceeds to step 3704. In step 3702 the values in theallowable recovery time field 3307 of path state control table 330 aresearched, and an instruction sent to the optical switching unit 20 tomask the interface warning (alarm) information when changing the statewithin the time that was set.

Then in step 3703, the optical switching unit 20 is instructed to setthe power control state of the applicable interface to the normal state.

If not changing to the operating state, then in step 3704 the opticalswitching unit 20 is instructed to set the power control state of theapplicable interface to a state where power consumption is small.

The above process is capable of reducing power consumption of the sparepath.

This invention is effective on network systems where control isimplemented by way of GMPLS protocols. This invention is particularlyeffective for reducing the power consumption on the redundant path.

1. A network system comprising: a path control unit that sets a mainpath and a spare path; and a plurality of data transfer units thattransfer data according to instructions from the path control unit;wherein the main path and the spare path provide alternative pathsbetween a first one of the data transfer units and a second one of thedata transfer units, wherein each of the data transfer units includes aninterface for transferring data, and a power control unit for reducingpower consumption in the interface in a non-operating state, wherein thepath control unit sets the spare path based on the connection status ofat least one of the data transfer units and the power consumptionreduction capacity of the at least one of the data transfer units,wherein one of the power control units sets a respective interface onthe spare path to a power-saving state when the spare path is set in thenon-operating state, and wherein the one of the power control unitschanges the respective interface on the spare path from the power-savingstate to a normal state when the spare path is set in an operatingstate.
 2. A network system according to claim 1, wherein the pathcontrol unit disregards error information from the respective interfaceon the spare path for a specified period while the power control unit ischanging the respective interface on the spare path from thepower-saving state to the normal state.
 3. A network system according toclaim 1, wherein when setting the spare path, the path control unitnotifies other path control units of the allowable recovery time forshifting the respective interface on the spare path from thenon-operating state to the operating state, as one portion of thesetting information.
 4. A network system according to claim 3, whereinthe interfaces contain multiple power saving states with different timesrequired for shifting to respective normal states, and wherein the pathcontrol unit sets the respective interface on the spare path to apower-saving state that can be shifted to the normal state within theshortest allowable recovery time from among the allowable recovery timesfor all of the interfaces along the spare path, when setting therespective interface on the spare path to a power-saving state.